Electric candle



Aug. 20, I92 9.

w. BLACK ELECTRIC CANDLE Filed Aug. 4, 1927 5 R Y W Mm m m 1B vA A m m w Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM A. BLACK, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO LUMINEX CORPORATION, A CORPORATION OF NEW JERSEY.

ELMTRIC CANDLE.

Application filed August 4, 1927. Serial No. 210,518.

This invention relates to electric candles designed to realistically simulate real candles of the burning-wick t pe.

The present invention is closely related to the subject matter of my co-pending application Serial No. 122,620, filed July 15, 1926, of which it is a continuation in part, and has to do with an improvedelectric candle structure of the same general type.

As in the case of the invention described in my aforementioned co-pending application the primary object underlying the present invention is to produce an electric candle which is as realistic in its simulation of a burning-wick candle as it is possible to attain. Other objects of the invention have to do with the production of an electric candle structure which is well adapted for economical manufacture on a large scale.

In electric candles according to the present invention the candle flame is simulated by means of a miniature electric bulb wrapped with a suitable translucent material, such as tissue paper treated with shellac, and formed into the shape of a candle flame. This is capable of producing a very realistic candle flame effect. In order to carry out this idea, however, the constriction at the base of the electric flame must be of very small diameter, that is, of the order of the diameter of a candle wick of ordinary size. For that reason it has been found impractical to use electric bulbs with standard basesthe smallest standard base being much too large for this purpose in an electric candle of ordinary size. For commercial reasons it has been found to be almost mandatory that these electric candles be designed and constructed with removable flames so that when the lamps burn out it is not necessary to replace the whole candle. By the term flame, as used throughout this specification, what is meant is the simulated flame comprising an electric bulb with its wrapper. Due'to the essential narrow constriction at the base of the flame it proved to be a diflicult problem to produce a removable flame which could be manufactured on a commercial scale to sell at a reasonable price. To accomplish this has been one of the important objects of this invention and it has been done in a most satisfactory way as will be described hereinafter.

In addition to the problem of producing a satisfactory removable flame other objects leading up to this invention have been to produce a candle body structure which is entirely satisfactory from both a mechanical and electrical standpoint and which is well adapted for volume production and capable, of course, of being manufactured at low unit cost. The candle body structure described herein accomplishes these objects in a very satisfactory manner.

The several novel features of this invention may best be described and pointed out in connection with the illustrations contained in the drawing specification and in which Fig. 1 is an enlarged elevational view of a miniature incandescent electric bulb and special base ada ted to form a part of the electric candle ame Fig. 2 is a cross-sectional view taken along the line 22 of Fig. 1;

Fig. 3 is a longitudinal sectional view of the upper end of the interior part of an electric candle body and showing in cross section a special screw socket designed to receive the electric flame;

Fi 4 is a cross-sectional view taken along the llne 4-4 of Fig. 3; and

Fig. 5 is an elevational view, partially in section, of a complete electric candle in accordance with this invention.

Referring first to Fig. 5 which shows the entire electric candle in elevation, the principal parts of the candle structure comprise the electric flame which is designated as a whole by the numeral 1, the body portion which is designated as a whole by the numeral 2, and a standard screw base which is designated by numeral 3. "As is indicated by the drawing the electric flame 1 is made to represent as realistically as possible a burningwick candle flame. To carry out this effect the base of the flame is reduced to a very small diameter. The body portion 2 is comwhich accompanies this posed of a rigid core 3' with an exterior 4 of a 7 for the present purpose. This is due partly to its tendency to crack in cold weather. Clear stearic acid may be used successfully but its cost is somewhat greater than that of parafiin. As a result of experimentation it has been found that a mixture of parafiin and stearic acid in about the proportions specified above will avoid the cracking due to low temperatures, and the cost is considerably less than that of pure stearic acid. Numerous other waxes and substances which are really wax-like in appearance may be used instead of parafiin or stearic acid. The whole object in this respect, of course, is to obtain a realistic simulation of a candle, and in order to accomplish this end the material used for the exterior of the candle body must be either a real wax or look so much like it as to deceive the eye.

In Fig. 1 there is illustrated on an enlarged scale, a miniature bulb and special base which constitutes one of the important features of this invention. The electric bulb, per se. is designated by the numeral 5. This bulb comprises a glass envelope of the form shown which encloses a small filament and has a sealoif tip at the bottom. A pair of lead-in wires 6 and 7 extend from the interior through the wall of the glass envelope above the sealoff tip. These lead-in wires are the conductors by which current is supplied to the filament. The special base of this lamp which is designated as a whole by reference numeral 8 is of necessity of very small outside diameter. This is essential in order to carry out the effect of the narrow constriction at the base of the electric flame. The preferred type of bulb having the tip at the bottom also aids in this result, as is pointed out in my prior application referred to. In practice this base is made about itnds of an inch outside diameter. It consists of a sleeve 9 made of brass tubing externally threaded, as indicated at 10, for a portion of its length. The upper end of sleeve 9 is provided with a lateral slot as indicated at 11. j The inside diameter of this sleeve is necessarily very small and, because of the fact that it is necessary to run a conductor through it, the problem of insulation between the sleeve and the conductor running through its center was a difficult one to solve. That is to say, it proved difficult to devise a suitable construction which would be well adapted for large scale manufacturing. The conductor 12 which, as shown, extends through the brass sleeve 9 may conveniently be a common brass pin with its sharp point cut ofi. The head of the pin is indicated at 13. The lead-in conductor 6 is soldered or brazed to the pin conductor 12. A second conductor 14 which may be a small piece of copper wire is soldered or brazed to the sleeve 9 and to the lead-in wire 7. Conductors 12 and 14 follow generally the contour of the lower part of the bulb from the seal-01f tip at the bottom to the points on the sides of the ulb where the lead-in wires pass thru the g1 ss. The slot 11 is made Wide enough to accommodate the wire 14 and the pin 12 with its insulation.

It is obvious that the pin 12 must be thoroughly insulated from the sleeve 9 and the conductor 14 because otherwise the filament lighting current would be short-circuited. To provide proper and dependable insulation in such a small space and at the same time design a base structure which would be entirely satisfactory from the mechanical as well as manufacturing standpoint was indeed a difiicult problem. This has been accomplished by the seemingly simple expedient of winding the pin 12 with fine thread and securing the thread to the pin by means of a quick-hardening insulating varnish. The varnish which is employed is known commercially as bakelite varnish and is presumably a phenolic formaldehyde product. Any insulating cement or varnish which will set quickly would probably be satisfactory. In applying the insulating thread to the pin 12 a winding machine of special design is used. The point of the pin is secured in a suitable chuck. The free end of the thread is secured to the chuck. and an automatic feeding device moves the thread along longitudinally of the pin while the chuck and pin revolve. A small amount of bakelite varnish is applied to the thread while it is being wound on the pin and at the same time or immediately thereafter a blast of hot air is directed at the insulated pin. This causes the varnish to set immediately thereby preventing the thread from unwinding. The outer diameter of the insulation thus applied is proportioned to provide a snug fit for the insulatedpin within the sleeve 9. The insulating thread is wound on the pin to such a length as to avoid any possibility of short-circuiting be tween the pin and the sleeve 9. In the drawing the thread is indicated as extending to a point 15. The pin head 13 forms one of the electric contacts while the sleeve 9 forms the other. In winding the thread on the pin it is best to wind several turns just under the head of the pin to form a sort of cushion for the pin head and prevent short-circuiting which might otherwise result from a longitudinal movement of the pin when the base is screwed into its socket.

A serious difliculty which was encountered in the construction of electric flames. especially those having a screw base as illustrated in Fig. 1. consisted in the breaking off of the lead-in wires 6 and 7 at the point of juncture with the supporting conductors 12 and 14. It was found that these joints were subject to frequent breakage due to 'insufiicient support for the electric bulb. After extensive experiment it was found that this trouble could be completely overcome by means of the application of a quick-drying insulating extend downto the screw base 3 and are solcement through which the light will pass; a cent comprising a quick-hardening solution of nitro-cellulose, on eneral sale, has been found especially satisfactory. A thin coating of this cement is practically transparent, but as the thickness is increased, the degree of transparency becomes less and the color deepens to an amber shade. The cement is applied to the lower part of the bulb including the junctions between the lead-in wires and the supporting conductors 12 and 14. It forms a strong skin adhering to the glass e11- velope and to the conductors 12 and 14 which provide a sort of supporting crotch for the bulb. permitting twisting of the bulb for the purpose of screwing it in and out of its socket without danger of breakage. The structure shown in Fig. 1 is rovided with a wrapper 16 which is shown in Fig. 5. 'This wra per may conveniently consist of white tissue paper which has been treated with shellac and allowed to dry. The shellacked paper is wrapped about the bulb and manipulated int-o the form shown to simulate a candle flame. It is secured to the bulb with the mentioned cement; and an application of the same cement is applied to the outside of the wrapper. This cement dries quickly and forms a very rigid coating. The application of shellac to the tissue paper gives to it a desirable degree of translucency and a color which causes the light to resembled closely that of a real candle flame.

The next problem to be encountered was (I) provide a suitable socket to receive the electric'flame and which would be entirely satisfactory mechanically and electrically and at the same time be capable of being manufactured at very low cost. Such a socket is illustrated in cross-section in Fig. 3. It comprises a piece of round brass rod 17 drilled and tapped axially as indicatedat 18 and recessed as shown. The thread 18 is designed to receive the threaded base 8. A-

be of the form shown or even a. common brass pin with its point cut off extends through the axis of the plug 19 and is rigidly held therein. The pin 20 forms the center contact which makes electrical engagement with the head 13 of the-pin 12 forming part of the base of the electric flame.

The socket comprising the parts 17 19 and 20 is seated in the end of the wooden dowel 3', a counterbored recess being provided for that purpose. A pair of conductors 21 and 22 make connection with the pin 20 and part 17, respectively, and are soldered thereto. These conductors which may be of bare wire dered thereto, one going to the center contact and the other to the screw shell which form the contacting elements of the base. The upper end of the wooden core 3' is slotted laterally as indicated in Fig. 3 and the cross sectional view Fig. 4. This slot need extend-but a short distance. Its purpose is to provide a convenient passageway for the conductors 21 and 22 and particularly for the former which is connectedto the center contact pin 20. The wooden core 3 is selected of a diameter slightly greater than the inside diameter of the screw base 3. Its lower end is provided with two lateral slots at right angles to each other. This permits contraction and expansion of the core allowing it to be forced readily into the screw base 3 and at the same time it provides a suitable passageway for the conductor 21 which extends to the center contact of the screw base 3.

The whole structure, as will be noted, is very simple and lends itself admirably to economical production. The socket comprising parts 17, 19 and 20 is obviously well adapted for rapid production at low cost. The wooden core is designed with a view to cheap production and at the same time to the facilitation of assembling operations. One feature which may not on its face seem important. but which is in reality quite important, is that the conductors 21 and 22 may be bare wires since there is no possibility of a short circuit between them. This saves the cost of cleaning off insulation which is a material consideration.

The base 3 is secured to the core 3' by means of a prick-punching operation which is performed by a die. The upper part of the base is prick-punched thereby being forced into the wooden core and is thus prevented from rotating when the candle is screwed into the socket.

In the manufacture of these electric candles the whole interior assemblage including the wooden core, the screw base 3, the socket at the upper end and the conductors 21 and 22 is cbmpleted before the wax is applied. The

interior assemblage comprising the elements mentioned is placed in a specially designed mold in which it is centered by means of the screw base 3 at one end and a long brass pin at the other end which engages the thread 18. The pin just mentioned fills the opening 18 thereby preventing the hot wax from running' into it, and at the same time this pin functions to center the core in the mold. After the wax, which is poured into the mold, has solidified, the candle body together with its centering pin are removed from the mold and a hot convex iron is applied to the upper end of the candle to melt the excess wax which is allowed to flow down the side of the candle to produce the effect of a partially burned candle, as illustrated in Fig. 5. After this operation is completed the centering pin is removed and the candle body is then ready to receive the electric flame. The process of manufacture which has just been described is an important feature of the present invention.

The miniature lamps which are used in these electric candles operate on six volts. This voltage is obtained from the usual 110 volt house-lighting circuits either by means of small step-down transformers, or resistance which may be incorporated in the lamp cord connected to the candle holder.

The life of the lamps is several hundred hours and they consume very little current. The total cost of operation including lamp relacements is so low and the effect is so real- 1stic that these electric candles are far more satisfactory and economical to use than ordinary candles.

I claim:

1. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having a filament and a pair of lead-in wires, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor extending through said sleeve and insulated therefrom, said conductor being rigidly connected to one of said lead-in wires, a second conductor connected to said sleeve and rigidly connected to the other of said lead-in wires, said conductors forming rigid supports for said bulb.

2. An electric flame designed to simulate a candle flame, comprisin an incandescent electric bulb having a lament and a pair of lead-in wires, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor extending through said sleeve and insulated therefrom, one end of said conductor being rigidly connected to one of said lead-in wires, the other end of said conductor forming a contact member, the insulation between said conductor and said sleeve consisting of thread wound on said conductor and secured thereto, a second conductor connected to said sleeve and rigidly connected to the other of said lead-in wires, said conductors forming rigid supports for said bulb.

3. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having a filament and a pair of lead-in wires, a base for said bulb comprising a tubular conducting sleeve of small diameter, said sleeve being threaded externally to engage a socket, a conductor extending through said sleeve and insulated therefrom, said conductor being rigidly connected to one of said lead-in wires, a second conductor being connected to said sleeve and rigidly connected to the other of said lead-in wires, said conductors forming rigid supports for said bulb.

4. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having a filament and a pair of lead-in wires, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor extending through said sleeve and insulated therefrom, said conductor having an enlarged end portion forminr a contact element, said conductor being rigidly connected to one of said lead-in wires, a second conductor connected to said sleeve and rigidly connected to the other of said lead-in wires, said conductors forming rigid supports for said bulb.

5. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having a filament and a pair of lead-in wires, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor extending through said sleeve and insulated therefrom, one end portion of said conductor bein rigidly connected to one of said lead-in wires, the other end of said conductor being enlarged to form a contact member, the insulation between said conductor and said sleeve consisting of thread wound on said conductor and secured thereto, a second conductor connected to said sleeve and rigidly connected to the other of said lead-in wires, said conductors forming rigid supports for said bulb.

6. A supporting base for an electric bulb comprising a tubular conducting sleeve, a conductor extending through said sleeve and insulated therefrom, the insulation between said sleeve and said conductor comprising thread wound on said conductor and adhesively secured thereto, and a second conductor rigidl attached to said sleeve, both of said con uctors being sufliciently stiff to rigidly support an electric bulb.

7 An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having a filament and a pair of lead-in wires, a pair of conductors each connected to one of said lead-in wires, said eonductors being adapted to support said bulb through their connections to said lead-in wires and also to conduct current to said bulb, and an adhesive coatin applied conjointly to the exterior of said bull) and said conductors, said coating providin mechanical reinforcement between said bu b and said conductors.

8. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having an enclosed filament, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor connecting said sleeve with one terminal of said filament, said conductor forming a support for said bulb, and a second conductor extending through said sleeve and insulated therefrom, said second conductor being connected at one end to the other terminal of said filament and forming a second support for said bulb.

Ill

9. An electric flame designed to simulate a candle flame, comprising an incandescent electric bulb having an enclosed filament, a base for said bulb comprising a tubular conducting sleeve of small diameter, a conductor connecting said sleeve with one terminal of said filament, said conductor forming a sup port for said bulb, a second conductor extending throu h said sleeve and insulated therefrom, sai second conductor being connected at one end to the other terminal of said filament and forming a second support for said bulb, and an adhesive reinforcement applied jointly to said bulb and said conductors so as to strengthen the attachment therebetween.

10. An electric lamp intended to simulate the flame of a burningfandle, comprising an incandescent electric ulb having a pointed tip at the bottom thereof,'a filament in said bulb, lead-in wires eiztending thru said bulb at points between said tip and the top of said bulb and connected to said filament, conductors secured to said wires and following gen-.

erally the outside contour of the bulb from said points to the extremity of said tip, and transparent adhesive means securing said conductors to said bulb whereby said bulb is rigidly supported by said conductors.

11. An electric lamp intended to simulate the flame of a burnin candle, comprising an incandescent electricfiiulb having a pointed tip at the bottom thereof, a filament in said bulb, lead in wires for the filament extending thru said bulb at points between said tip and the top of said bulb, conductors secured to said wires and following generally the outside contour of the bulb from said points to the extremity of said tip, and transparent adhesive means entirely enveloping said bulb, said means being point-shaped at the top of said bulb and serving to secure said conductors to said bulb.

In testimony whereof I aifix my signature.

WILLIAM A. BLACK. 

